Electronic Telegram No. 1273 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2008ar IN IC 3284 F. Yuan, University of Michigan; R. Quimby, California Institute of Technology; D. Chamarro, M. D. Sisson, and C. Akerlof, University of Michigan; and J. C. Wheeler, University of Texas, on behalf of the ROTSE collaboration, report the discovery of a supernova in unfiltered CCD images taken with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory. The supernova is located at R.A. = 12h24m37s.92, Decl. = +10o50'17".4 (equinox 2000.0), which is 5".3 east and 3".1 south of the center of IC 3284; 2008ar was discovered on Feb. 27.25 UT at mag about 16.9 and imaged again on Feb. 28.25 at mag about 16.0. A spectrogram (range 420-890 nm) of 2008ar, obtained on Feb. 28.29 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. Rostopchin and A. Westfall, shows it to be a type-Ia supernova. The data are similar to the pre-maximum spectra of normal type-Ia supernovae, such as SN 1992A (Kirshner et al. 1993, Ap.J. 415, 589), but with features significantly extended to the blue. Correcting for the SDSS redshift of the host (z = 0.026), the minimum of the Si II 635.5-nm feature is blueshifted by 14300 km/s. The Ca II infrared absorption is unusually strong, and the line minimum is blueshifted by 23600 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2008 CBAT 2008 February 29 (CBET 1273) Daniel W. E. Green